Field of the Invention
Embodiments of the invention relate to a touch sensor integrated type display device, such as a touch sensor integrated type display device capable of increasing a touch performance by improving touch accuracy at a corner or an edge.
Discussion of the Related Art
In recent years, various input devices, such as a keyboard, a mouse, a track ball, a joystick, and a digitizer, have been used to allow users to interface with home appliances or information telecommunication devices. However, as a user makes use of these input devices, the user may become dissatisfied due to the need to learn how to use the input devices. Furthermore, these input devices occupy physical space. Thus, there has been an increased demand for a convenient and simple input device capable of reducing erroneous operations. In response to the demand, a touch sensor has been proposed to enable the user to input information by directly touching a screen, or by approaching the screen with his or her hand or a pen while he or she watches the display device. Such a display device can be applied to, for example, a home appliance or an information telecommunication device.
The touch sensor may a simple configuration capable of reducing erroneous operations. The user may be able to perform an input action without using a separate input device, and can quickly and easily manipulate a display device implementing such a touch sensor through the contents displayed on the screen. Thus, the touch sensor has been applied to various display devices.
The touch sensor may be classified into an add-on type touch sensor, an on-cell type touch sensor, and an integrated type (or in-cell type) touch sensor, depending on its structure. The add-on type touch sensor may be configured such that the display device and a touch panel including the touch sensor are individually manufactured, and then the touch panel may be attached to an upper substrate of the display device. The on-cell type touch sensor may be configured such that the touch sensor may be directly formed on the surface of an upper glass substrate of the display device. The in-cell type touch sensor may be configured such that the touch sensor may be mounted inside the display device to thereby achieve a thin profile display device and increase the durability of the display device.
However, because the add-on type touch sensor has a structure in which the touch sensor is mounted on the display device, there is a problem of an increase in a thickness of the display device. Further, the visibility of the display device may be reduced by a reduction in brightness of the display device resulting from the increase in the thickness of the display device.
The on-cell type touch sensor is formed on the surface of the glass substrate of the display device and thereby shares a glass substrate with the display device. Therefore, a thickness of the display device using the on-cell type touch sensor may be less than a thickness of the display device using the add-on type touch sensor. However, the entire thickness of the display device using the on-cell type touch sensor may increase because of a touch driving electrode layer, a touch sensing electrode layer, and an insulating layer for insulating the touch driving electrode layer and the touch sensing electrode layer, which constitute the on-cell type touch sensor.
The in-cell type touch sensor may solve the problems generated in the add-on type touch sensor and the on-cell type touch sensor, providing advantages of a thin profile and an improvement in durability. The in-cell type touch sensor may be divided into a light type touch sensor and a capacitive touch sensor, depending on a method for sensing a touched portion. The capacitive touch sensor may be subdivided into a self capacitive touch sensor and a mutual capacitive touch sensor.
The self capacitive touch sensor may form a plurality of independent patterns in a touch area of a touch sensing panel and measure changes in a capacitance of each independent pattern, thereby deciding whether or not a touch operation is performed. The mutual capacitive touch sensor may cross X-axis electrode lines (for example, driving electrode lines) and Y-axis electrode lines (for example, sensing electrode lines) in a touch electrode formation area of a touch sensing panel to form a matrix, apply a driving pulse to the X-axis electrode lines, and sense changes in voltages generated in sensing nodes defined as crossings of the X-axis electrode lines and the Y-axis electrode lines through the Y-axis electrode lines, thereby deciding whether or not a touch operation is performed.
Hereinafter, an example related art self capacitive touch sensor integrated type liquid crystal display is described with reference to FIG. 1. FIG. 1 is a plane view showing a related art self capacitive touch sensor integrated type liquid crystal display.
As shown in FIG. 1, the self capacitive touch sensor integrated type liquid crystal display may include an active area AA, in which touch electrodes are formed and data may be displayed, and a bezel area BA positioned outside the active area AA. In the bezel area BA, various wires, a source driving and touch sensing integrated circuit (IC) 10, and a gate driver IC 20 may be formed.
The active area AA may include a plurality of touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm divided in a first direction (for example, x-axis direction) and a second direction (for example, y-axis direction) crossing the first direction and a plurality of routing wires TW11-TW1m, TW21-TW2m, TW31-TW3m, . . . , and TWn1-TWnm which may be respectively connected to the plurality of touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm and may be arranged in parallel with one another in the second direction.
The plurality of touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm in the active area AA may be formed by dividing a common electrode of the liquid crystal display, and thus operate as common electrodes in a display drive for displaying data and operate as touch electrodes in a touch drive for touch recognition.
The bezel area BA positioned outside the active area AA may include the source driving and touch sensing IC 10, the gate driver IC 20, and various wires. In the display drive, the source driving and touch sensing IC 10 drives gate lines (not shown) of the liquid crystal display and supplies display data to data lines (not shown). In the touch drive, the source driving and touch sensing IC 10 supplies a touch driving voltage to the touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm and scans changes in a capacitance of each touch electrode before and after the touch of each touch electrode, thereby determining a position of the touched touch electrodes. The various wires include the routing wires TW11-TW1m, TW21-TW2m, TW31-TW3m, . . . , and TWn1-TWnm connected to the touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm, the data lines connected to the source driving and touch sensing IC 10, and the gate lines connected to the gate driver IC 20.
In the related art self capacitive touch sensor integrated type liquid crystal display having the above-described structure, when a finger or a conductive metal such as a stylus pen touches the active area AA of the liquid crystal display, the source driving and touch sensing IC 10 may sense changes in a capacitance of the touch electrode before and after the touch electrode is touched, and may determine a touch position. For example, the source driving and touch sensing IC 10 may apply a driving pulse to the touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm formed in the active area AA and then may sense changes in a self capacitance of each of the touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm before and after the touch of each touch electrode, thereby determining the touch position.
Next, an example of the accuracy of touch sensing depending on the touch position is described with reference to FIG. 2. FIG. 2 is a plane view showing a partial area of FIG. 1 for an explanation of touch accuracy depending on a touch position in the related art touch sensor integrated type liquid crystal display.
FIG. 2 shows changes in a capacitance at each of touch positions ‘a’ to ‘d’. As shown in FIG. 2, because each of the touch electrodes Tx11-Tx1m, Tx21-Tx2m, Tx31-Tx3m, . . . , and Txn1-Txnm should accurately sense a touch position of the finger or the stylus pen, each touch electrode may have a very small size. Thus, when a touch operation is performed on the touch sensor integrated type liquid crystal display, one touch electrode as well as the adjacent touch electrode may be touched together.
Further, when the finger or the stylus pen touches the touch electrode, the touch sensitivity may increase in proportion to a contact area between them. Thus, the touch sensitivity obtained when the touch operation is performed at a corner or an edge of the active area AA may be less than the touch sensitivity obtained when the touch operation is performed on an inner side of the active area AA.
For example, when the four touch electrodes Tx22, Tx23, Tx32, and Tx33 at an inner touch position ‘a’ of the active area AA shown in FIG. 2 are touched, a change amount of a capacitance of each of the four touch electrodes Tx22, Tx23, Tx32, and Tx33 before and after the touch of each touch electrode may be accumulated and measured. Because the change amount of the capacitance of each of the four touch electrodes Tx22, Tx23, Tx32, and Tx33 is accumulated and calculated depending on their touch area, an accurate touch position may be sensed.
However, when the touch operation is performed at an edge (i.e., a touch position ‘b’ or ‘c’) of the active area AA shown in FIG. 2, only the two touch electrodes Tx21, Tx31; or Tx11, Tx12 may be touched. In this example, a change amount of a capacitance of each of the two touch electrodes Tx21, Tx31; or Tx11, Tx12 before and after the touch of each touch electrode may be accumulated and measured. However, because the change amount of the capacitance of each of the two touch electrodes Tx21, Tx31; or Tx11, Tx12 is accumulated and calculated depending on their touch area, the touch sensitivity at the edge touch position ‘b’ or ‘c’ may be less than the touch sensitivity at the inner touch position ‘a’.
Further, when the touch operation is performed at a corner (i.e., a touch position ‘d’) of the active area AA shown in FIG. 2, only one touch electrode Tx11 may be touched. In this example, a change amount of a capacitance of the one touch electrode Tx11 before and after the touch of the touch electrode Tx11 may be measured. Because the change amount of the capacitance of the touch electrode Tx11 may be calculated depending on its touch area, the touch sensitivity at the corner touch position ‘d’ may be less than the touch sensitivity at the edge touch position ‘b’ or ‘c’.
As described above, because a magnitude of the capacitance may vary depending on a touch position, the change amount of the capacitance may decrease when the touch position is close to the edge and/or the corner of the active area AA. Hence, the touch accuracy and linearity at the edge and the corner of the active area AA may be reduced.
Next, an example related art mutual capacitive touch sensor integrated type liquid crystal display is described with reference to FIG. 3. FIG. 3 is a plane view showing a related art mutual capacitive touch sensor integrated type liquid crystal display.
As shown in FIG. 3, the mutual capacitive touch sensor integrated type liquid crystal display may include an active area AA, in which touch electrodes are formed and data may be displayed, and a bezel area BA positioned outside the active area AA. In the bezel area BA, various wires, a source driving and touch sensing IC 10′, and a gate driver IC 20′ may be formed.
The active area AA may include a plurality of first touch electrodes Tx11-Tx14, Tx21-Tx24, Tx31-Tx34, and Tx41-Tx44 divided in a first direction (for example, x-axis direction) and a second direction (for example, y-axis direction) crossing the first direction, a plurality of first sub-routing wires TW11-TW14, TW21-TW24, TW31-TW34, and TW41-TW44 which may be respectively connected to the plurality of first touch electrodes Tx11-Tx14, Tx21-Tx24, Tx31-Tx34, and Tx41-Tx44 and extend in the second direction, and a plurality of second touch electrodes Rx1 to Rx3 which may be disposed between the first touch electrodes Tx11-Tx41 and Tx12-Tx42; Tx12-Tx42 and Tx13-Tx43; and Tx13-Tx43 and Tx14-Tx44, which may be adjacent to each other in the first direction, and may be arranged in the second direction.
The plurality of first touch electrodes Tx11-Tx14, Tx21-Tx24, Tx31-Tx34, and Tx41-Tx44 may be connected to one another using the first sub-routing wires TW11-TW14, TW21-TW24, TW31-TW34, and TW41-TW44 respectively connected to the first touch electrodes, first connection wires TW1C to TW4C, and first main routing wires TW1 to TW4 and may form a plurality of first touch electrode lines Tx1 to Tx4 arranged in the first direction.
For example, the 1-1 touch electrodes Tx11 to Tx14 of a first row arranged in the first direction may be connected to one another using the 1-1 sub-routing wires TW11 to TW14 respectively connected to the 1-1 touch electrodes Tx11 to Tx14, the 1-1 connection wire TW1C connecting the 1-1 sub-routing wires TW11 to TW14, and the 1-1 main routing wire TW1 connected to the 1-1 connection wire TW1C and may form the 1-1 touch electrode line Tx1 of the first row.
The 1-2 touch electrodes Tx21 to Tx24 of a second row arranged in the first direction may be connected to one another using the 1-2 sub-routing wires TW21 to TW24 respectively connected to the 1-2 touch electrodes Tx21 to Tx24, the 1-2 connection wire TW2C connecting the 1-2 sub-routing wires TW21 to TW24, and the 1-2 main routing wire TW2 connected to the 1-2 connection wire TW2C and may form the 1-2 touch electrode line Tx2 of the second row.
The 1-3 touch electrodes Tx31 to Tx34 of a third row arranged in the first direction may be connected to one another using the 1-3 sub-routing wires TW31 to TW34 respectively connected to the 1-3 touch electrodes Tx31 to Tx34, the 1-3 connection wire TW3C connecting the 1-3 sub-routing wires TW31 to TW34, and the 1-3 main routing wire TW3 connected to the 1-3 connection wire TW3C and may form the 1-3 touch electrode line Tx3 of the third row.
The 1-4 touch electrodes Tx41 to Tx44 of a fourth row arranged in the first direction may be connected to one another using the 1-4 sub-routing wires TW41 to TW44 respectively connected to the 1-4 touch electrodes Tx41 to Tx44, the 1-4 connection wire TW4C connecting the 1-4 sub-routing wires TW41 to TW44, and the 1-4 main routing wire TW4 connected to the 1-4 connection wire TW4C and may form the 1-4 touch electrode line Tx4 of the fourth row.
In the plurality of second touch electrodes Rx1 to Rx3, the 2-1 touch electrode Rx1 may be disposed between the first touch electrodes Tx11 and Tx12; Tx21 and Tx22; Tx31 and Tx32; and Tx41 and Tx42, which may be adjacent to each other in the first direction, and may form a 2-1 touch electrode line Rx1 of a first column.
The 2-2 touch electrode Rx2 may be disposed between the first touch electrodes Tx12 and Tx13; Tx22 and Tx23; Tx32 and Tx33; and Tx42 and Tx43, which may be adjacent to each other in the first direction, and may form a 2-2 touch electrode line Rx2 of a second column.
The 2-3 touch electrode Rx3 may be disposed between the first touch electrodes Tx13 and Tx14; Tx23 and Tx24; Tx33 and Tx34; and Tx43 and Tx43, which may be adjacent to each other in the first direction, and may form a 2-3 touch electrode line Rx3 of a third column.
The bezel area BA positioned outside the active area AA may include the source driving and touch sensing IC 10′, the gate driver IC 20′, and various wires.
The gate driver IC 20′ may drive gate lines (not shown) of the liquid crystal display in a display drive.
The source driving and touch sensing IC 10′ may supply display data to data lines (not shown) of the liquid crystal display in the display drive. In a touch drive, the source driving and touch sensing IC 10′ may sequentially supply a touch driving voltage to the 1-1 to 1-4 touch electrode lines Tx1 to Tx4 and then sense the 2-1 to 2-3 touch electrode lines Rx1 to Rx3. The source driving and touch sensing IC 10′ may scan changes in a mutual capacitance generated between the 1-1 to 1-4 touch electrode lines Tx1 to Tx4 and the 2-1 to 2-3 touch electrode lines Rx1 to Rx3 before and after the touch of each touch electrode and determine a position of the touched touch electrodes.
The various wires may include the 1-1 to 1-4 sub-routing wires TW11-TW14, TW21-TW24, TW31-TW34, and TW41-TW44 which may be respectively connected to the 1-1 to 1-4 touch electrodes Tx11-Tx14, Tx21-Tx24, Tx31-Tx34, and Tx41-Tx44 and extend from the active area AA to the bezel area BA, the 1-1 connection wire TW1C connecting the 1-1 sub-routing wires TW11 to TW14, the 1-2 connection wire TW2C connecting the 1-2 sub-routing wires TW21 to TW24, the 1-3 connection wire TW3C connecting the 1-3 sub-routing wires TW31 to TW34, the 1-4 connection wire TW4C connecting the 1-4 sub-routing wires TW41 to TW44, the 1-1 to 1-4 main routing wires TW1 to TW4 respectively connecting the 1-1 to 1-4 connection wires TW1C, TW2C, TW3C, and TW4C to the source driving and touch sensing IC 10′, second routing wires RW1 to RW3 connected to the second touch electrode lines Rx1 to Rx3, the gate lines (not shown) connected to the gate driver IC 20′, and the data lines (not shown) connected to the source driving and touch sensing IC 10′.
The first and second touch electrodes Tx11-Tx14, Tx21-Tx24, Tx31-Tx34, Tx41-Tx44 and Rx1 to Rx3 in the active area AA may be formed by dividing a common electrode of the liquid crystal display, and thus operate as common electrodes in the display drive for displaying data and operate as touch electrodes in the touch drive for recognizing the touch position.
In the mutual capacitive touch sensor integrated type liquid crystal display having the above-described example structure, when a finger or a conductive metal, such as a stylus pen, touches the active area AA of the liquid crystal display, the source driving and touch sensing IC 10′ may sense changes in a capacitance between the first and second touch electrodes close to a touch position before and after the touch of each touch electrode and may determine the touch position. For example, the source driving and touch sensing IC 10′ may sequentially apply a driving pulse to the first touch electrode lines (touch driving electrode lines) Tx1 to Tx4 of the active area AA and then may sense changes in the mutual capacitance generated between the first touch electrode lines Tx1 to Tx4 and the second touch electrode lines (touch sensing electrode lines) Rx1 to Rx3 before and after the touch of each touch electrode through the second touch electrode lines Rx1 to Rx3, thereby determining the touch position.
Next, an example of the accuracy of touch sensing depending on the touch position is described with reference to FIG. 4. FIG. 4 is a plane view showing a partial area of FIG. 3 for an explanation of touch accuracy depending on a touch position.
In the touch sensor integrated type liquid crystal display shown in FIG. 4, the first and second touch electrode lines Tx1-Tx4 and Rx1-Rx3 may be formed by dividing the common electrode formed in the active area AA. The mutual capacitance of each of the first and second touch electrode lines Tx1-Tx4 and Rx1-Rx3 of the active area AA may vary depending on their position. For example, the touch electrodes at an edge and a corner of the active area AA have relatively small mutual capacitance. Hence, changes in the mutual capacitance at the edge and the corner of the active area AA may be small.
FIG. 4 shows example change in a capacitance at each of touch positions ‘1’ to ‘4’. As shown in FIG. 4, when a touch operation is performed at the touch position ‘1’, a change amount of a mutual capacitance between the 1-3 touch electrode Tx13 and the 2-2 touch electrode Rx2 before and after the touch operation and a change amount of a mutual capacitance between the 1-3 touch electrode Tx13 and the 2-3 touch electrode Rx3 before and after the touch operation may be accumulated, and a total change amount of the mutual capacitance may be calculated.
When the touch operation is performed at the touch position ‘2’, a change amount of a mutual capacitance between the 1-3 touch electrode Tx13 and the 2-3 touch electrode Rx3 before and after the touch operation and a change amount of a mutual capacitance between the 1-4 touch electrode Tx14 and the 2-3 touch electrode Rx3 before and after the touch operation may be accumulated, and a total change amount of the mutual capacitance may be calculated.
When the touch operation is performed at the touch position ‘3’, a change amount of a mutual capacitance between the 1-4 touch electrode Tx14 and the 2-3 touch electrode Rx3 before and after the touch operation may be calculated as a total change amount of the mutual capacitance.
When the touch operation is performed at the touch position ‘4’, a change amount of a mutual capacitance between the 1-4 touch electrode Tx14 and the 2-3 touch electrode Rx3 before and after the touch operation may be calculated as a total change amount of the mutual capacitance. However, because an edge of the 1-4 touch electrode Tx14 is touched at the touch position ‘4’, the change amount of the mutual capacitance at the touch position ‘4’ may be less than the change amount of the mutual capacitance at the touch position ‘3’.
In the change amounts of the mutual capacitance at the touch positions ‘1’ to ‘4’, the change amounts of the mutual capacitance at the touch positions ‘ 1’ and ‘2’ may be similar, and the change amount of the mutual capacitance at the touch position ‘3’ may be less than the change amounts of the mutual capacitance at the touch positions ‘1’ and ‘2’ and may be greater than the change amount of the mutual capacitance at the touch position ‘4’.
As described above, because the magnitude of the mutual capacitance varies depending on the touch position, the change amount of the mutual capacitance may decrease as the touch position is close to the edge and/or the corner of the active area AA. Hence, the touch accuracy and linearity at the edge and the corner of the active area AA may be reduced.
In other words, as described above, the touch accuracy and the linearity of both the self capacitive touch sensor integrated type liquid crystal display and the mutual capacitive touch sensor integrated type liquid crystal display may be reduced at the edge and the corner of the active area AA. Therefore, there is a need for an improved measurement technique to prevent this.